With the proliferation of third-party applications, or apps, on user devices there is a trend towards users fulfilling their domain-specific search needs by utilizing an app specialized for that domain instead of using a Web-based search service. For example, a user searching for nearby restaurants may go directly to his or her URBANSPOON® app to find restaurants and reviews instead of using a search service such as BING®. The result is a diversion of traffic away from Web-based search services.
Further, although search services are effective in crawling and indexing information, the information is currently limited to publicly available information. Information regarding a user's engagement history with a particular app is by and large protected through a user login and is generally not available to search services. As well, content associated with these apps is not available for consumption by Web-based search services. For example, BING® cannot crawl and index a user's EXPEDIA® itinerary. This makes it difficult for search services to fully answer user intent when providing Web-based search results.